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The Effects of Persistent Pollutants

Persistent pollutants, often labeled "Persistent Organic Pollutants" (POPs), are referred to as such because of the organic nature of the compounds leaving those pollutants resistant to natural degradation processes in the environment. Pollutants able to resist natural chemical, biological and photolytic processes persist in the environment for extended periods of time, accumulating in the tissues of living organisms -- often concentrating in the food chain -- creating harmful effects of the environment and health. Though there are some natural POPs, most are created through industrial processes and often used as pesticides.

  1. The Problem of Long-Range Transport

    • One of the most persistent aspects of such pollutants is the ability to transport over long ranges, causing contamination in places that have never produced such pollutants through human engineered industrial processes. This phenomenon has made POPs a global problem, even affecting areas such as the Arctic. Persistent pollutants are carried by both wind and water over long distances, often being deposited far from where they were originally used or produced. According to the Environmental Protection Agency (EPA), this means that countries that have banned POPs may not see a decline in their concentrations because other countries are still manufacturing and using them.

    Risks to the Food Chain

    • Another major issue is the ability of POPs to persist and spread through the food chain. With POPs accumulating in the tissues of living organisms, they are easily transported from one species to the next aided by migration patterns and natural predatory activity on land and in the sea. POPs embed themselves in the body fat of living organisms and actually become more concentrated as they move from one species to the next, a process termed "biomagnification." Just a small amount of POPs at the bottom of the food chain, through biomagnification, can have major consequences on predators at the top of the food chain.

    Impact on Health of Living Organisms

    • Multiple scientific studies have concluded serious health risks for all types of species, humans, birds, other mammals and fish in particular. POPs are linked to declines in populations, diseases and abnormalities such as birth defects. Scientists have found that POPs disrupt the reproductive process, stunt the developmental process, affect the behavioral processes, impact neurological processes and even suppress immunological processes. Humans are at risk mainly through the food chain. Diets consisting of fish and wild animals high in fat content are usually the most high-risk diets for exposure to POPs.

    Mitigating the Risks

    • The most important effort to tackle the problem of POPs globally comes in the form of the Stockholm Convention on Persistent Organic Pollutants, finalized in 2001. Participating government bodies from around the world agreed to reduce and/or eliminate the production and use of POPs. The objective of the convention is to protect the environment, wildlife and human health from exposure to POPs. The convention covers 12 chemicals produced to include such well-know hazards as DDT and PCBs. The Stockholm Convention is managed by the United National Environment Program and seeks to expand the original 12 chemicals to include other POPs identified through scientific inquiry.

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